Efficiency improvement for a polarizing color filter based on submicron metal grating

A polarizing color filter, combining the function of polarizer and color filter, is proposed and theoretically investigated. The proposed color filter comprises of a metal grating and a dielectric layer on a glass substrate. The influence of the geometrical parameters of dielectric layer on the transmission efficiency are discussed in detail by rigorous coupled-wave analysis (RCWA). The result shows that a dielectric layer of high equivalent refractive index can enhance its performance effectively. A optimum tricolor filter with more than 74.1% broadband transmission and a polarization extinction ratio of 8.39dB is obtained. For TE-polarized light, it is reflected and can be recycled in the backlight units to increase the total energy utility. The numerical result shows that the peak transmission efficiency can increase 21.5% by using the proposed devices.